Wire gripping crimping dies with rib receiving grooves



March 24, 1959 H. w. BATCHELLE-R 2,878,854

WIRE GRIPPING CRIMPING DIES WITH RIB RECEIVING cRoov s Filed May Is,1956 United I States Patent WIRE GRIPPING CRIMPING DIES WITH RIBRECEIVING GROOVES Hugh W. Batcheller, Newton, Mass.,assiguor to KentMfg. Corp., Newton, Mass., a corporation of Massachusetts ApplicationMay 16, 1956, Serial No. 585,362

2 Claims. (Cl. 153-1) This invention relates to dies for crimpingelectrical terminals onto wires to make a permanent connection between aterminal and a wire which will be mechanically strong and electricallyeflicient. Electric terminals are secured to wires in a variety of waysthe commonest of which is by being crimped. For this purpose the clipportion of the terminal which is to be crimped about a die being astationary anvil with a cylindrically hollowed seat on which the clip tobe crimped is placed. The upper die or rolling tool has a bottom faceconsisting of two planes which converge upwardly and merge in acylindrical curve having a curvature equal to that of the clip portionof the terminal after it has been crimped about a wire. Any amount ofpressure short of injuring the wire may be applied between the dies inthe crimping operation, but to have a good mechanical and electricalconnection the wire must be strongly gripped after the dies have beenseparated and the crimped metal has relaxed. The amount of suchrelaxation depends largely on the stiffness of the elements which arecrimped. If these elements are made of stock that is too thin, forexample, the grip on the wire may be too weak for a good mechanicalconnection, and the electrical resistance of the connection may sooneror later become excessive. To obtain a better grip with stock of anyweight, the elements which are to be crimped about the wire may bestifiened by indenting one or more grooves in the inner face thereofwith resultant ribs or ridges projecting from the outer face thereof.These ribs are arranged so that when the clips are crimped about a wire,the ribs will extend circumferentially around the wire. To avoidflattening of the ribs by the crimping dies, the active faces of thedies are grooved to accommodate the rib or ribs on the grippingelements, these grooves being for the most part at least as deep as theribs are high. Thus the crimping is done without impairing thestiffening eifect of the rib or ribs. However, added tightness of thejunction is obtained by decreasing the depth of a portion of the groovein the rolling tool to about half the height of the rib. When the diesoperate to crimp a clip about a wire, the end portions of the rib whichmeet at the top of the wire are partly mashed by the shallow portion ofthe groove in the rolling tool. This presses the adjacent portions ofthe clip strongly against the wire and compacts it if the wire is of thestranded variety. The rib reduces the tendency to relax after thepressure is relieved.

For a more complete understanding of the invention, reference may be hadto the following description of certain embodiments thereof, and to thedrawing, of which:

Figure 1 is a fragmentary elevational view of dies embodying theinvention, about to crimp the clip portion of a connector member;

2,878,854 Patented Mar. 24, 1959 Figure 2 is a similar view of the diesafter the clip has been partially crimped;

Figure 3 is a section on the line 3-3 of Figure 1;

Figure 4 is a section on the line 4-4 of Figure 1;.

Figure 5 is a fragmentary elevational view of dies of a modified formabout to crimp the clip portion of a connector member;

Figure 6 is a similar view of the dies, shown in Figure 5 after the cliphas been partially crimped;

Figure 7 is a section on the line 7-7 of Figure 5;

Figure 8 is a section on the line 88 of Figure 5;

Figure 9 is an elevational view of the dies shown in Figures 1 and 2 atthe completion of the crimping stroke;

Figure 10 is an elevational view of the dies shown in Figures 5 and 6 atthe completion of the crimping stroke;

Figure 11 is a plan view of a connector member with its clip portioncrimped on a wire; and

Figure 12 is a plan view of a connector member crimped to a wire whichenters from a side of the member.

A set of crimping dies for crimping the clip portion of a terminal orconnector member to a wire is shown in Figures 1, 2 and 9. The lower dieor anvil 20 has a narrow seat 22 which is cylindrically dished orrecessed to be fitted by a portion of a U-shaped clip 24 of a terminalmember or connector member 26. The member 26 conventionally shown inFigure 3 has a clip portion 24 which includes pointed fingers projectingin opposite directions from the longitudinal axis of the member and bentinto an open loop or U-shape to receive a wire 28 about which thefingers are to be crimped. The clip 24 is formed with a rib 30 whichextends at right angles to the axis of the member so as to stiffen thefingers of the clip 24 mechanically. The rib 30 is made by indenting agroove in the inner face of the clip, causing the rib 30 to project fromthe outer face of the clip. The seat 220i the anvil 20 is provided witha groove 34 of sufiicient width and depth to receive and protect aportion of the rib 30 when a clip is placed on the seat of the anvil.

Above the lower die or anvil 20 is an upper die or rolling tool 40. Thetwo dies are mounted for relative movement toward and from each other.Preferably the lower die is fixed while the upper die is verticallymovable by any suitable power press as well known in the art. The lowerend of the rolling tool 40 is shaped like an inverted V with a roundedapex. In other words, the lower end has two upwardly converging faces 42and 44 which mergeinto and are connected by a cylindrical surface 46'. Acontinuous groove 48 is provided in the faces 42, 46, 44 to receive therib 30 of the clip which is to be crimped. This groove is in a commonvertical plane with the groove 34 in the lower die so that when thelower portion of the rib 30 of a clip is seated in the groove 34, theupper portions of the rib will progressively enter the groove 48 as theclip is being curled or crimped by downward movement of the upper die.When the upper die descends, the fingers of the clip are curled inwarduntil the clip assumes a cylindrical or tubular form as indicated inFigure 2. Since the rib 30 rides in the grooves 34 and 48, it is notflattened by the pressure thus far exerted in the crimping operation.

According to the present invention, the midportion 50 of the groove 48,that is, some of the groove 48 which is in the rounded surface 46, is ofless depth than the remainder of the groove, the depth of this portionof the groove being less than the height of the rib 30. At the apex ofthe active surface of the upper die the groove 50 may have a depth equalto about half the height of the rib 30 and may also be somewhat narrowerthan the rib. After the upper die presses down form, it continues itsdownward movement to press the clip tightly on the wireJP; If thecross-sectional area of the wire 28 is less than that of the inside ofthe clip when the latter is curled to the tubular form indicated inFigure 2, portions of the clip "will overflow the sides of the narrowanvil '20 as indicated in Figure 9 so that the wire will be tightlyconfined and squeezed within the clip. In this pressing operationthe'variation in depth of the groove 48 is of special significance. Thedeep parts of the groove in the faces 42 and 44 protect thecorresponding portions of the rib from being flattened. The shallowerportion .of the groove, however, has the effect of partially flatteningand narrowing the portions 7 of the rib adjacent to the. line where thefingers'of the clip 24 meet when the clip is crimped, as indicated inFigure 11. Thus the top of the clip is heavily pressed on the wire'28but the'rib on the sides and bottom of.

the clip is left with its full height to stiffen the clip and thus tominimize relaxation thereof when the pressure of the dies is relieved.The almostcrushing pressure exerted by the rolling tool 40 in theprocess of partially flattening a portion of the rib at the top of theclip tends to compact the wire if it is of the stranded variety andensures a tight mutual .engagement between the wire and clip which has avery low resistance comparing favorably with that of a weldedconnection.

Figures 5 to 8 and 10 illustrate a'pair of dies which operate on asimilar principle but are designed to crimp the clip portion of anelectric terminal or connector member to a wire which comes in from theside of the member instead of being in line with the axis thereof.Figure 12 shows a connector member of this type having a clip portion 62adapted to be crimped about a wire 64. The clip 62 is bent into an openloop, as indicated in Figure 5, including a portion 66 in the form of ashallow trough and an upstanding portionadapted to be curled over in thecrimping operation to surround a wire 64 laid in the trough. Theupstanding portion may consist of one or more fingers 68, two beingshown in Figures 7 and 12. To stiffen the fingers 68, a rib 70 is formedin each to project from the. outersurface thereof. The ribs are made byindenting grooves in the inner surface of the clip, the grooves andridges extending lengthwise of the fingers 68 so that when the clip iscrimped about a wire, each rib will encircle the wire as indicated inFigures 6 and 10.

To crimp the clip 62, two dies 72 and 74 are employed. The lower die oranvil 72 ispreferably fixed and has a hollowed seat 76 in its top tosupport the trough portion of the clip 62. The upper die or rolling tool74 is V mounted to move up and down over the anvil 72. This die has arecess 80 therein with an inner surface having a-portion 82 like aninverted trough directly above the anvil 72. The seat 76 has grooves 84to receive part of the ribs'70, and the recess in the upper die isgrooved as at 86 to receive other-parts of the ribs 70, the grooves inthe two dies being disposed in common vertical planes for this purpose.These grooves are at least as deep as the ribs 70 are high, except thatthe grooves 86 each have a portion 88 which is shallower and narrower sothat when the final pressure comes on the clip, the end portion of eachrib 70 will be partially flattened and narrowed and the pressure of theupper die will be transmitted to the wire to consolidate it if it is ofthe stranded type. The upper die is so arranged with reference to theanvil that the vertical wall 90 of the recess is "offset from the side92 of the. anvil as indicated in'Figures 6 and 10. This is to providespace into which some of the clip can overflow if the wire 28 is notlarge enough to fill the tubular cavity formed when the clip has beencrimped or curled to the tubular form shown in Figure 6." Furtherdescent of theupper diesqueezes the clip tightly against the wire 28 asindicated in Figure 10.

'Theribs70 are preserved, except for the end portion of each, tomaintain the stiffness of the clip.

die, the lower end'of said upper die having two upwardly convergingfaces merging into a rounded connecting face,

said seat and said faces having therein portions of a groove disposed ina vertical plane, the portion of the groove in the rounded face having alesser depth than the other portions.

2. Apparatus for crimping about a wire a sheet metal clip having a ribembossed thereon and arranged to encircle the wire when the clip hasbeen crimped thereon, said apparatus comprising a lower die with aseat'to support the clip, and an upper die having at its lower end twoupwardly converging faces and a rounded surface connecting said faces,said seat and said faces having therein portions of a groove arranged toreceive said rib, said rounded surface having a groove thereinconnecting the grooves in said faces but of a lesser depth thanthat ofthe said grooves.

References Cited in the file of this patent UNITED STATES PATENTS676,292 Wittel June 11, 1901 1,836,497 Phelps Dec. 15, 1931 1,870,364Jones Aug. 9, 1932 2,335,414 Hinrichs Nov. 30, 1943 2,716,275 'MatthysseAug. 30, 1955 2,799,191 Barnes July 16, 1957

